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untillnesss/bresenham_circle.dart

Created June 5, 2024 03:05
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  1. untillnesss created this gist Jun 5, 2024.
    66 changes: 66 additions & 0 deletions bresenham_circle.dart
    View file
    Original file line number Diff line number Diff line change
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    class Point {
    final int x,y;

    Point(this.x, this.y);

    @override
    String toString() {
    return "(${this.x}, ${this.y})";
    }
    }

    List<Point> bresenhamCircle(int xc, int yc, int r) {
    /*
    This function implements Bresenham's circle algorithm to generate points on a circle.
    Args:
    xc: X-coordinate of the circle center.
    yc: Y-coordinate of the circle center.
    r: Radius of the circle.
    Returns:
    A list of Point objects representing (x, y) coordinates of points on the circle.
    */
    int x = 0;
    int y = r;
    int d = 3 - 2 * r;

    List<Point> circlePoints = [];
    while (x <= y) {
    // Add points for the current octant
    circlePoints.add(Point(xc + x, yc + y));
    circlePoints.add(Point(xc + x, yc - y));
    circlePoints.add(Point(xc - x, yc + y));
    circlePoints.add(Point(xc - x, yc - y));
    circlePoints.add(Point(xc + y, yc + x));
    circlePoints.add(Point(xc + y, yc - x));
    circlePoints.add(Point(xc - y, yc + x));
    circlePoints.add(Point(xc - y, yc - x));

    // Update decision parameter and coordinates for next point
    if (d < 0) {
    d = d + (4 * x) + 6;
    } else {
    d = d + (4 * (x - y)) + 10;
    y -= 1;
    }
    x += 1;
    }

    return circlePoints;
    }

    // Use the list of circlePoints to draw the circle on your canvas (e.g., using CustomPainter)
    int main(){


    // Example usage
    int centerX = 50;
    int centerY = 50;
    int radius = 20;

    List<Point> circlePoints = bresenhamCircle(centerX, centerY, radius);

    print(circlePoints);
    return 0;
    }